Dual-Band and Low-Profile Differentially Fed Slot Antenna for Wide-Angle Scanning Phased Array

A novel dual-band slot antenna with low profile is proposed. The slot antenna is constructed on dual-layer substrates, in which a metal cavity is fabricated by metalized vias. The antenna is fed by a differential scheme, so it can be easily integrated with other systems. The proposed antenna can operate at dual resonant frequencies because of the metal cavity and the radiating slot. A corresponding differential feeding network is constructed on another substrate. The half-power beamwidth of the slot antenna's radiation pattern is wide in the electric plane ( E-plane), and it is suitable to be applied to wide-angle scanning phased arrays. The phased array built by the slot antenna can realize wide-angle scanning within 3 dB peak gain fluctuation in the E -plane at both frequencies. Measured results show that the phased array can scan from -67° to 69° at 5.02 GHz and from -62° to 64° at 5.58 GHz.